JP4754099B2 - Method for producing water-soluble embossed film - Google Patents

Description

【００５１】
【発明の効果】
本発明では、ドラム又はベルト面上の表面粗さ（Ｒａ）が０．３〜１０μｍである梨地模様を有するドラム又はベルト上で水溶性フィルムを製膜した後、該フィルムを凹凸形状の深さが１００〜４００μｍである凹凸形状が刻印されたエンボスロールとバックアップロールの間を通過させてエンボス加工を行い、該フィルム面に表面粗さ（Ｒａ）が０．１〜８μｍの梨地模様と１００メッシュ以下で深さが５０〜３００μｍの凹凸模様を形成させるので、得られた水溶性エンボスフィルムは、ロール状に巻いて保存したり、高温高湿下で長期間放置したときにも耐ブロッキング性に優れ、テカリがなく、高級品感に優れ、耐ピンホール性に優れるもので、かかるフィルムは、農薬、薬剤、染料、洗剤、肥料、化粧品、生理用品等の包材として有用で、特に各種薬剤等のユニット包装用として非常に有用である。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a water-soluble embossed film excellent in blocking resistance, high-quality feeling, and pinhole resistance.
[0002]
[Prior art]
Conventionally, a packaging material made of a water-soluble film such as a polyvinyl alcohol film has been widely used as a material for housing agricultural chemicals, drugs, dyes, detergents, fertilizers, cosmetics, sanitary products, and the like. Utilizing the water-solubility of the film, it can be used directly in an aqueous medium to decompose or dissolve the packaging material to obtain a solution, or when the packaging material opened at the time of use is poured into water and discarded. ing. Such a water-soluble film is practically surface-treated. For example, (1) a satin treatment is applied to the water-soluble film for matting or blocking prevention, or (2) the blocking property is improved. In addition, embossing for forming an uneven shape on the film is performed. As an example of the latter, as disclosed in JP-A-7-290567, the thickness of the concave portion is 15 to 25 μm (the thickness of the convex portion is 20 to 100 μm). ), A method for producing an embossed water-soluble film having a tensile strength of 2.5 to 4.5 kg / mm ² has been proposed.
[0003]
[Problems to be solved by the invention]
However, when the present inventor examined the above-mentioned conventional technology, in this conventional technology, in terms of blocking resistance, a large number of films were stacked and stored for a long time under high temperature and high humidity, or a long film was used. It has become clear that when rolled and stored for a long period of time, the effect is limited, so-called shininess of the film is generated, and a high-quality product with a sense of thickness and three-dimensionality is poor. There is a high demand for high-quality products in the market, and there is a need for a water-soluble embossed film that does not block even under such severe conditions.
[0004]
[Means for Solving the Problems]
Therefore, the present inventor formed a water-soluble film on a drum or belt having a satin pattern having a surface roughness (Ra) on the drum or belt surface of 0.3 to 10 μm , and then formed the film into an uneven shape. The embossing is carried out by passing between an embossing roll and a backup roll imprinted with a concavo-convex shape having a depth of 100 to 400 μm , and a satin pattern with a surface roughness (Ra) of 0.1 to 8 μm on the film surface And found that a method for producing a water-soluble embossed film that forms a concavo-convex pattern having a depth of 50 to 300 μm with a mesh size of 100 mesh or less can achieve the above object, and has completed the present invention.
[0005]
DETAILED DESCRIPTION OF THE INVENTION
The present invention is described in detail below.
The water-soluble resin that is a raw material of the water-soluble film of the present invention is not particularly limited, and examples thereof include various resins of synthetic or natural product derivatives such as polyvinyl alcohol resins, carboxymethyl celluloses, starch polyethylene oxides, and pullulans. Examples of the material include polyvinyl alcohol resins.
[0006]
The polyvinyl alcohol-based resin is usually produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate, but is not necessarily limited to this in the present invention, and a small amount of unsaturated carboxylic acid (salt, Ester, amide, nitrile and the like), olefins, vinyl ethers, unsaturated sulfonates, polyoxyalkylene allyl ethers and the like.
[0007]
Among these polyvinyl alcohol resins, the saponification degree is particularly preferably 70 to 100 mol%, and more preferably 75 to 99 mol%. If the degree of saponification is less than 70 mol%, the water solubility tends to deteriorate, which is not preferable.
[0008]
The average degree of polymerization is preferably 300 to 4000, more preferably 500 to 3000. If the average degree of polymerization is less than 300, the strength of the film is inferior.
[0009]
In the present invention, after forming a water-soluble film on the drum or belt having a satin pattern using the above-mentioned water-soluble resin, the film is passed between an embossing roll and a back-up roll engraved with an uneven shape. Embossing is performed, and the surface roughness (Ra) of the film surface is 0.1 to 8 μm, preferably 0.4 to 5 μm, particularly 0.8 to 4 μm, and 100 mesh or less, preferably 20 to It is characterized by forming a concavo-convex pattern of 80 mesh and a depth of 50 to 300 μm, preferably 120 to 240 μm. If the surface roughness (Ra) is less than 0.1 μm, the blocking resistance is inferior. If it exceeds 8 μm, the pinhole resistance is inferior and is inappropriate.
On the other hand, if the concavo-convex pattern exceeds 100 mesh, the blocking resistance is inferior, and a high-quality film cannot be obtained.
If the depth of the concavo-convex pattern is less than 50 μm, a sufficient apparent film thickness cannot be obtained, and if it exceeds 300 μm, the pinhole resistance is inferior and the object of the present invention cannot be achieved.
[0010]
The surface roughness (Ra) mentioned here is measured by a laser microscope (for example, an ultra-deep shape measuring microscope, “VK-8510” manufactured by Keyence Corporation), and the depth of the uneven pattern is JIS. It is measured by the method of B 0601.
[0011]
Examples of the concavo-convex pattern that satisfies the above conditions include a lattice pattern, a silk pattern, a tortoiseshell pattern, a rhombus pattern, etc. Among them, it is a silk pattern in terms of luxury and blocking resistance. preferable.
[0012]
Next, a method for forming a water-soluble film from the above water-soluble resin on a drum or belt having a satin pattern will be described.
In the present invention, the drum indicates a normal rotating heat drum, and the belt indicates an endless belt.
Such a drum or a belt, a surface roughness on the surface (Ra) is 0.3 to 10 [mu] m, more 0.5～7Myuemu, especially be those 1~5μm the satin finish is formed preferable.
[0013]
Specifically, as a method of forming a satin pattern on the drum or belt, 1) a method of treating the surface of the drum or belt with a sand blast method, a chemical mat method, an etching method, or a resin coating method with a filler, 2) a transistor pulse power source A processing method using an electric discharge machine is used.
[0014]
As the film forming method, the above water-soluble resin is cast as an aqueous solution on a drum or belt, and then dried, or the water-soluble resin alone or a composition to which a plasticizer is added is heated and melted on the drum or belt. And a method of extruding.
Examples of the plasticizer include polyhydric alcohol plasticizers such as glycerin, diethylene glycol, and triethylene glycol, and water. At the time of film formation, in addition to antioxidants such as phenols and amines, stabilizers such as phosphate esters, coloring agents, fragrances, extenders, anti-packaging agents, release agents, ultraviolet absorbers, inorganic powders, interfaces Ordinary additives such as activators may be added.
Of the above film forming methods, the former method is preferable, and such a method will be described below.
[0015]
The concentration of the aqueous resin solution used in the casting method is preferably 15 to 40% by weight. If the concentration is less than 15% by weight, the productivity is poor, and if it exceeds 40% by weight, the solution is highly viscous and the workability is poor. Absent. The aqueous solution is preferably cast at a temperature of 60 to 98 ° C. If the temperature is less than 60 ° C., the solution has a high viscosity and the workability is poor.
[0016]
The drying temperature of the film is preferably 80 to 180 ° C. If the temperature is less than 80 ° C, drying takes time and workability is poor, and if it exceeds 180 ° C, peeling from the drum or belt may be difficult.
[0017]
The film thickness of the film obtained by the above drying is not particularly limited, but is preferably 10 to 120 μm, more preferably 15 to 80 μm, and if it is less than 10 μm, the mechanical strength is insufficient, and 120 μm. Exceeding this is undesirable because it leads to a decrease in water solubility and film formation efficiency.
Further, the moisture content of the film is preferably adjusted to 1.0 to 10% by weight, and further adjusted to 2 to 8% by weight. When the moisture content is less than 1.0% by weight, the film is hard. Thus, the embossing in the next step is not sufficiently performed, and if it exceeds 10% by weight, the strength of the film tends to decrease, which is not preferable.
[0018]
Next, the water-soluble film on which the satin pattern obtained as described above is formed is subjected to the following embossing using an embossing roll and a backup roll on which the unevenness is formed.
[0019]
The embossing roll is preferably 100 mesh or less, more preferably 80 mesh or less, and particularly preferably 20 to 80 mesh. The depth is 100 to 400 μm , and further, an embossed shape with 150 to 300 μm is used. Is preferred.
[0020]
Such embossing is preferably carried out continuously after the above film formation.
The surface to be embossed may be any surface of the water-soluble film having a satin pattern, but it is preferable in terms of blocking resistance to perform the process by bringing the surface having the satin pattern into contact with the embossing roll surface.
[0021]
Such an embossing roll is manufactured by a method of giving a silk pattern on the surface of a metal roll or a ceramic roll with a seed pattern having a silk pattern, and performing plating or the like as necessary.
The material of the metal roll is not particularly limited, but examples thereof include iron, SUS, mild steel, hard steel, chrome steel, nickel steel, cast steel, brass and the like, and the ceramic roll material includes aluminum oxide and silicon dioxide. , Silicon nitride, silicon carbide and the like.
[0022]
The backup roll is preferably a rubber roll, a cotton roll, or a paper roll coated with a synthetic rubber such as urethane, silicone, fluorine, or olefin.
[0023]
When a rubber roll is used as such a backup roll, it is preferable to use a roll having a surface hardness of A50 ° to A95 °, more preferably A55 ° to A95 °, particularly A60 ° to A95 °.
If the surface hardness of the roll is less than A50 °, an embossed film having a sufficient apparent film thickness cannot be obtained. If the roll hardness exceeds A95 °, an apparent film thickness can be obtained, but a sufficient uneven shape cannot be transferred. Pinholes are easily generated, which is not preferable.
[0024]
When a cotton roll or paper roll is used, it is preferable to use one having a roll surface hardness of D50 ° to D90 °, more preferably D55 ° to D85 °, particularly D60 ° to D85 °.
If the surface hardness of the roll is less than D50 °, an embossed film with a sufficient apparent thickness cannot be obtained, and if it exceeds D90 °, an apparent thickness can be obtained, but a sufficient uneven shape cannot be transferred. Holes are easily generated, which is not preferable.
Here, the surface hardness is a hardness obtained by a measuring method according to JIS K 6301.
[0025]
The pressing force applied to the water-soluble film when the water-soluble film is passed between the embossing roll and the backup roll is usually preferably 10 to 150 kg / cm, more preferably 30 to 100 kg / cm.
[0026]
If the pressing force is less than 10 kg / cm, embossing with a sufficient depth cannot be achieved, and if it exceeds 100 kg / cm, the thickness of the embossed film is partially reduced and the mechanical strength is reduced, and pinholes are generated. It tends to be unfavorable.
[0027]
Moreover, it is preferable that the surface temperature of the embossing roll at the time of embossing is 100-200 degreeC, and the surface temperature of a backup roll is adjusted to 50 degreeC or more. A more preferable surface temperature of the embossing roll is 105 to 170 ° C., particularly preferably 110 to 160 ° C., and a more preferable surface temperature of the backup roll is 60 to 110 ° C., and particularly preferably 65 to 100 ° C.
[0028]
If the surface temperature of the embossing roll is less than 100 ° C., embossing with a sufficient depth cannot be achieved, and if it exceeds 200 ° C., the solubility of the film is lowered, which is not preferable. Further, when the surface temperature of the backup roll is less than 50 ° C., it is not preferable because embossing having a sufficient depth cannot be obtained.
[0029]
The water-soluble embossed film thus obtained is rolled up into a product. The water-soluble embossed film obtained in the present invention is excellent in blocking resistance even when a considerably strong pressure is applied between the films or when it is stored under exposure to a high temperature and high humidity atmosphere. There is no shine, and there is a sense of quality, and it is also excellent in pinhole resistance. It is useful as a packaging material for agricultural chemicals, drugs, dyes, detergents, fertilizers, cosmetics, sanitary products, etc. Very useful for unit packaging.
[0030]
【Example】
Hereinafter, the present invention will be specifically described with reference to examples.
In the examples, “%” means weight basis unless otherwise specified.
Example 1
[0031]
[Production of drums]
Sand blasting was performed on an iron rotating heat drum so that the surface roughness (Ra) was 3 μm. Such treatment was performed using a blasting apparatus (“FDO type” manufactured by Fuji Seisakusho) with a nozzle pressure of 3 kg / cm ² and a ceramic abrasive # 100.
[Production of endless belt]
The endless belt made of iron was coated with a filler-containing fluororesin and dried to adjust the surface roughness (Ra) to 3 μm.
[0032]
[Formation of satin pattern]
A 25% aqueous solution of a polyvinyl alcohol-based resin [average polymerization degree 1400, saponification degree 88 mol%] is adjusted to 90 ° C., cast on a rotary heat drum at 93 ° C., dried at 130 ° C., and a moisture content of 6%. A polyvinyl alcohol film was obtained.
[0033]
The film was embossed using the following embossing roll and backup roll.
[Preparation of embossing roll]
The surface of the iron embossing roll was given a silk pattern (depth: 180 μm) with a 40-mesh silk pattern seed roll.
[0034]
[Backup role]
As the backup roll, a rubber roll manufactured by Yuri Roll Co., Ltd. (roll surface hardness A80 °) coated with synthetic rubber was used.
[0035]
(Manufacture of water-soluble embossed film)
The embossing roll heated to 120 ° C. and the back-up roll heated to 65 ° C. have a pressing force of 50 kg / cm and a film passing speed of 15 m / min. Was embossed to obtain a water-soluble embossed film having a surface roughness (Ra) of 2.4 μm and a 40-mesh silk pattern with a depth of 140 μm.
The following evaluation was performed about the obtained film.
[0036]
(Blocking resistance)
A. The obtained water-soluble embossed film 100 m was wound up in a roll shape (branch diameter: about 3 inch) at a tension of 3 kg / m and a winding speed of 10 m / min, and placed horizontally in an atmosphere of 30 ° C. × 80 RH%. After being left for a month, the roll was unwound and evaluated as follows.
○: Blocking was not recognized, and the roll could be smoothly unwound to the core part. X: Blocking was observed in the core part, and damage was observed on a part of the film during unwinding.
B. 100 sheets of the obtained water-soluble embossed film (200 × 200 mm) are stacked, and a 10 kg stainless steel cylinder is placed thereon with 100 mmφ, and after standing for 7 days in an atmosphere of 60 ° C. × 90% RH, the state is as follows. Evaluated.
○: Blocking was not recognized Δ: Blocking was slightly recognized, but was peeled off in units of one sheet.
X: blocking was observed, and the film was damaged when peeled off in units of one sheet.
(Shine)
The obtained water-soluble embossed film was illuminated with an incandescent lamp from an oblique 45 ° angle, and visually observed from the opposite 45 ° direction, and evaluated as follows.
○ ・ ・ ・ No shine is recognized × ・ ・ ・ Tekali is recognized [0039]
(Luxury)
The appearance of the obtained water-soluble embossed film was evaluated as follows.
○… There is a three-dimensional effect, and a high-quality impression is recognized. ×… There is no three-dimensional effect, and looks like a low-priced product.
Example 2
In Example 1, the same conditions were followed except that the sandblast nozzle pressure conditions were adjusted to change the drum satin pattern so that the surface roughness (Ra) was 4 μm, and the surface roughness (Ra) was 3.2 μm. A water-soluble embossed film in which a pattern and a 40-mesh silk pattern with a depth of 140 μm were formed was obtained and evaluated in the same manner.
[0041]
Example 3
In Example 1, the embossing roll was formed in the same manner except that the silk pattern was changed to 50 mesh, and a satin pattern with a surface roughness (Ra) of 2.4 μm and a silk pattern with a depth of 140 μm formed with 50 mesh. The obtained water-soluble embossed film was obtained and evaluated in the same manner.
[0042]
Example 4
In Example 1, except that the depth of the embossing roll was changed to 250 μm, a satin pattern having a surface roughness (Ra) of 2.4 μm and a silk pattern having a depth of 200 μm and 40 mesh. The water-soluble embossed film in which was formed was obtained and evaluated in the same manner.
[0043]
Example 5
In Example 1, the same procedure was used except that an endless belt having the same surface roughness was used instead of the rotating drum, and the surface roughness (Ra) was 2.4 μm satin pattern and 40 mesh with a depth of 140 μm. A water-soluble embossed film on which a pattern was formed was obtained and evaluated in the same manner.
[0044]
Example 6
In Example 1, it is performed in the same manner except that the embossing roll having a silk pattern is applied to the surface that does not have the satin pattern, and the surface roughness (Ra) is 0.7 μm and the depth is 40 mesh. A water-soluble embossed film on which a 140 μm silk pattern was formed was obtained and evaluated in the same manner.
[0045]
Comparative Example 1
In Example 1, the same procedure was followed except that the sandblast nozzle condition was adjusted to change the satin pattern of the drum so that the surface roughness (Ra) was 0.1 μm, and the surface roughness (Ra) was 0.08 μm. A water-soluble embossed film in which a satin pattern and a 40-mesh silk pattern having a depth of 140 μm were formed was evaluated in the same manner.
[0046]
Comparative Example 2
In Example 1, the same procedure was followed except that the sandblast nozzle pressure condition was adjusted to change the satin pattern on the drum so that the surface roughness (Ra) was 12 μm, and the satin pattern with a surface roughness (Ra) of 10 μm A water-soluble embossed film having a 40-mesh silk pattern with a depth of 140 μm was obtained and evaluated in the same manner.
[0047]
Comparative Example 3
In Example 1, except that the embossing roll was changed to 120 mesh, a satin pattern having a surface roughness (Ra) of 2.4 μm and a silk pattern having a depth of 140 μm were formed from 120 mesh. The obtained water-soluble embossed film was obtained and evaluated in the same manner.
[0048]
Comparative Example 4
In Example 1, except that the depth of the embossing roll was changed to 80 μm, a satin pattern having a surface roughness (Ra) of 2.4 μm and a silk pattern having a depth of 40 μm and a depth of 64 μm The water-soluble embossed film in which was formed was obtained and evaluated in the same manner.
[0049]
Comparative Example 5
In Example 1, except that the depth of the embossing roll was changed to 450 μm, a satin pattern having a surface roughness (Ra) of 2.4 μm and a silk pattern having a depth of 360 μm and a mesh of 40 μm were used. The water-soluble embossed film in which was formed was obtained and evaluated in the same manner.
[0050]
The results of Examples and Comparative Examples are shown in Table 1.

[0051]
【The invention's effect】
In the present invention, after forming a water-soluble film on a drum or belt having a satin pattern having a surface roughness (Ra) on the drum or belt surface of 0.3 to 10 μm, the film is formed to have an uneven depth. Is embossed by passing between an embossed roll and a back-up roll imprinted with a concavo-convex shape with a surface roughness (Ra) of 0.1 to 8 [mu] m and 100 mesh Since the concave / convex pattern having a depth of 50 to 300 μm is formed in the following, the obtained water-soluble embossed film can be stored in a roll or stored in a roll, or can be blocked for a long time under high temperature and high humidity. Excellent, no shine, excellent quality, and excellent pinhole resistance.This film is useful as a packaging material for agricultural chemicals, drugs, dyes, detergents, fertilizers, cosmetics, sanitary products, etc. In a very particularly useful for unit packaging of various drugs or the like.

Claims (5)

After forming a water-soluble film on a drum or belt having a satin pattern having a surface roughness (Ra) on the drum or belt surface of 0.3 to 10 μm, the depth of the concavo-convex shape is 100 to 400 μm. The embossing is performed by passing between an embossing roll and a back-up roll engraved with a concavo-convex shape, and the surface of the film has a surface roughness (Ra) of 0.1 to 8 μm and a depth of 100 mesh or less. Forming a concavo-convex pattern having a thickness of 50 to 300 μm.   2. The method for producing a water-soluble embossed film according to claim 1, wherein the embossing roll is brought into contact with the surface of the water-soluble film having a satin pattern.   The method for producing a water-soluble embossed film according to claim 1 or 2, wherein the uneven pattern is a silk pattern. Claim 1-3 manufacturing method of a water-soluble embossed film according to any one of water-soluble film is characterized in that it is a film in the casting process. Claim 1-4 manufacturing method of a water-soluble embossed film according to any one, wherein the water-soluble film is a polyvinyl alcohol film.